1. Field of the Invention
The present invention relates to a socket for a semiconductor device provided with a holding mechanism for selectively holding a semiconductor device in a releasable manner.
2. Description of the Related Art
A semiconductor device mounted to electronic equipment or others is subjected to various tests at a stage prior to being mounted thereto to remove latent defects thereof. Such tests are carried out while the semiconductor device is mounted to a socket for the semiconductor device, for example.
The socket for the semiconductor device made available for such tests is generally referred to as an IC socket and arranged on a printed wiring board having an input/output portion. The input/output portion is supplied with a predetermined test voltage and supplies an abnormal detection signal representing, for example, a short-circuit from the semiconductor device as an object to be tested.
As disclosed in Japanese Patent Laid-Open No. 2004-79227, the socket for the semiconductor device of an open-top type, for example, includes a socket body disposed on a printed wiring board (not shown), the socket body for accommodating a contact terminal group for electrically connecting the semiconductor device to the printed wiring board, a positioning member (in Japanese Patent Laid-Open No. 2004-79227, referred to as a positioning mechanism) having an accommodation portion wherein the semiconductor device is accommodated, disposed at a position above the contact terminal group in the socket body, a latch mechanism as a holding mechanism for selectively holding the semiconductor device relative to the accommodation portion of the positioning member, having a pair of presser members (in Japanese Patent Laid-Open No. 2004-79227, referred to as a latch) and arranged on the periphery of the positioning member, and a cover member (in Japanese Patent Laid-Open No. 2004-79227, referred to as an operating member) for transmitting the operating force applied thereto to the latch mechanism via a predetermined driving mechanism so that the presser member is operated.
The cover member has an opening at a center thereof for allowing the semiconductor device to pass therethrough when the semiconductor device is attached to or detached from the accommodation portion of the positioning member. The cover member is disposed so as to move up and down relative to the socket body, and is coupled to a driving mechanism. The driving mechanism is, for example, a link mechanism or a cam mechanism for coupling the cover member to a proximal end of the presser member of the latch mechanism so that the presser member is rotatable in accordance with ascent and descent of the cover member.
The positioning member is fixed to the socket body and determines relative positions of the terminals of the semiconductor device to the contact terminal group of the semiconductor device by positioning the outer periphery of the semiconductor device mounted into the accommodation portion of the socket body.
The pair of presser members in the latch mechanism are disposed opposite to each other with the intervention of the mounted semiconductor device therebetween, respectively. The presser member includes a proximal end supported rotative movably by the socket body and coupled to the above-mentioned driving mechanism, a contacting portion selectively brought into contact with or apart from the outer periphery of the semiconductor device, and a coupled portion for coupling the proximal end to the contacting portion.
When the semiconductor device is mounted into the accommodation portion, the contacting portion of the presser member occupies a waiting position apart from the accommodation portion not to interfere with the semiconductor device, and after the semiconductor device has been mounted in the accommodation portion, the a contacting portion of the presser member enters the accommodation portion and occupies a holding position.
In this structure, when the semiconductor device is mounted to the accommodation portion of the positioning member through the opening of the cover member, the cover member is pressed from an upper position to a lower position relative to the socket body and the positioning member at a predetermined stroke and held there, and the contacting portions of the above-mentioned pair of presser members are apart from each other relative to the accommodation portion of the positioning member to occupy the waiting position, whereby the mounting of the semiconductor device into the accommodation portion becomes possible.
Then, if the cover member is released from the held state, the cover member moves upward by a force of a biasing member to return to its initial position, the pair of presser members become closer to each other from the waiting position to the accommodation portion of the positioning member and are brought into sliding contact with the outer peripheral surface of a package of the semiconductor device so that terminals of the semiconductor device located by the positioning member are pressed toward the contact terminal group. Accordingly, the semiconductor device is held to the accommodation portion of the positioning member.